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The Sisler Lacrimal Canalicular Trephine
Hampson A. Sisler
The use of the canalicular minitrephine known as the Sisler trephine was reported in 1990.1,2 The minitrephine was developed to allow for opening a canaliculus that was occluded distally. Lacrimal trephines had been used earlier but were for different purposes, such as opening an occluded punctum or proximal canalicular obstruction and were larger in diameter.3
Anatomy
The lacrimal drainage system begins at the puncta in the medial aspect of the upper and lower eyelids, where they meet in the blink cycle. The proximal, vertical canaliculi merge into a sacculation at the point of right angle bend into the horizontal portion and, at said sacculation point, achieve their largest diameter of 1.5 mm. The upper and lower canaliculi continue horizontally, gradually narrowing to 0.15 mm in diameter, and then either join together at the point of entry into the lacrimal sac or enter it separately. It is in this distal canaliculus that obstruction occurs most frequently and is, because of its miniscule size, the most diffi cult to repair.
Instrumentation
The minitrephine is 16 mm long and 0.81 mm in diameter (sold by BD Visitec, Franklin Lakes, NJ) (Figure 28.1A and B). It has a plastic hub affi xed to the shaft proximally by which it can be grasped and rotated. An intraluminal stylet, provided with it, is removable (Figure 28.2). The hub is fashioned for a Luer lock, whereby it can be attached to a syringe, which can also be provided with a spring device for retracting the plunger when the rotating trephine to which it is attached gains entry into the patent lacrimal sac (Figure 28.3).
Technique
Topical anesthesia is fi rst placed on the eye. A nasociliary nerve block is achieved by injection of 1 mL of anesthetic through a 30-gauge needle directly along the nasal wall of the orbit, starting just above the medial canthal tendon and extending back 2 cm. The trephine is lubricated and made to enter the previously dilated proximal canaliculus and passed to the obstruction site (Figure 28.4). The trephine is rotated in a boring manner until the tip emerges into the lacrimal sac, at which time the spring-weighted plunger pops back and a cylinder of scar tissue passes into the lumen of the trephine or back into the barrel of the syringe.
FIGURE 28.1. (A and B) The Sisler minitrephine.
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The assembly is then withdrawn. This is followed by stenting by any preferred means. Postoperatively, antibiotic/steroid eye drops may be applied to the conjunctival cul-de-sac four times a day, or as desired.
Stents are typically left in place for about 6 weeks.
FIGURE 28.2. The Sisler minitrephine with partially removed intraluminal stylet. (Photo courtesy Adam J. Cohen, MD.)
FIGURE 28.3. The Sisler minitrephine with syringe and spring device. (Photo courtesy of Hampson A. Sisler, MD.)
FIGURE 28.4. The Sisler minitrephine passed into the left lower eyelid cana- liculus. (Photo courtesy of Adam J. Cohen, MD.)
Complications
Possible complications include damage to the proximal, nondiseased canaliculi by the invading trephine. Herein, prophylactic trephine lubrication is important. Before this, dilation of the proximal, normal canaliculus needs to be done carefully, following the normal anatomy to avoid trauma to it. The creation of a false passage with either instru- ment is to be avoided, and fi nalization in the lacrimal sac needs to be proven by irrigation of the passages on through the nasolacrimal duct before the emplacement of the stent or by the popping back of the plunger at the moment of entry. Moreover, the trephine should not be forcibly advanced, in order to minimize surgical trauma to these deli- cate structures.
Conclusion
The Sisler trephine makes recanalization of a distally blocked lacrimal canaliculus an offi ce procedure as opposed to major surgical microdis- section in an operating room setting. The uniform, cylindrically shaped bolus of scar tissue removal makes for a sculptured passageway through the previous obstruction which, with its smooth and clean edges, is less likely to reocclude with time.
References
1. Sisler HA, Allarakhia L. A new ophthalmic microtrephine. Ophthalmic Surg 1990;21:656–657.
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2. Sisler HA, Allarakhia L. New microtrephines make lacrimal canalicular rehabilitation an offi ce procedure. Ophthal Plast Reconstr Surg 1990;6:
203–206.
3. Veirs ER. Stenosis of the common canaliculus. Correction with a canalicular rod. Arch Ophthalmol 1969;81:569–570.
